1. Refer to figure A. Which student model would be most accurate if the gas in the balloon underwent a phase change and why?

• Student 2, because temperature is what causes particles to change in motion and arrangement, while thermal energy just represents the average kinetic energy of particles.
• Student 1, because thermal energy is what causes particles to change in motion and arrangement, while temperature just represents the average kinetic energy of the particles.
• Student 1, because whenever thermal energy is transferred out of a substance a phase change will occur, while temperature changes don’t always result in a phase change.
• Student 2, because whenever the temperature of a substance changes a phase change will occur, while thermal energy changes don’t always result in a phase change.

2. Refer to figure A. Which of the two student models accurately label the arrow to show what causes the particles in the balloon to change when it is placed near the liquid and why?

• Student 1, because thermal energy is transferred out of the balloon which would result in the particles inside having more kinetic energy which would explain why they stop moving and the temperature lowers.
• Student 2, because the temperature difference between the balloon and liquid is so large it causes the particles to change phase which is why they lose kinetic energy.
• Student 1, because thermal energy is transferred out of the balloon which would result in the particles inside having less kinetic energy which would explain why they move closer together and the temperature lowers.
• Student 2, because the temperature moves from the warmer particles in the balloon to the colder particles in the liquid, which shows why the temperature of the balloon lowers.

3. In the space below, draw a model to show the motion of the particles in the balloon and liquid before they touch and when they are touching.

4. Explain how your model shows the change in motion of the particles when the balloon and liquid touch.

5. Which of the following substances has observable properties most similar to the substance inside the balloon?

• Solid ice
• Liquid water
• Oxygen gas

6. Draw a diagram showing the difference in the motion of the particles in a glass of liquid water at room temperature and the liquid shown here.

7. The pressure inside the balloon is caused by particles colliding with the inside of the balloon. How does the kinetic energy of the particles relate to the pressure inside the balloon?

• Particles with higher kinetic energy will have no effect on the pressure inside the balloon.
• Particles with higher kinetic energy will cause the pressure inside the balloon to be higher.
• Particles with higher kinetic energy will only cause the pressure to change if the container is flexible and not rigid.
• Particles with higher kinetic energy will cause the pressure inside the balloon to be lower.

8. How can temperature explain the differences between the motion of the particles in liquid water and the liquid shown in this gif?

9. Refer to figure A. How should the inside of student 1’s deflated balloon be labeled and why?

• Low kinetic energy, because thermal energy was transferred out of the balloon into the liquid.
• Higher kinetic energy, because thermal energy was transferred out of the balloon but the motion of the particles changed.
• High kinetic energy, because changes in thermal energy have no effect on kinetic energy.
• No kinetic energy, because the particles in the balloon lost so much energy they stopped moving and changed phases.

10. How does thermal energy inside the balloon change and what effect does this have on the space between particles?

• Thermal energy inside the balloon decreases which causes the space between particles to decrease.
• Thermal energy inside the balloon increases which causes the space between particles to increase.
• Thermal energy inside the balloon increases which causes the space between particles to decrease.
• Thermal energy inside the balloon decreases which causes the space between particles to increase.

11. In the space below, draw a model to show how the motion of the particles in the balloon will change if we take the balloon out of the liquid and place it on a table at room temperature for an hour.

12. Explain how your diagram shows the changes in particle motion if the balloon is taken out of the liquid and placed on a table at room temperature for an hour.

13. If a particle is moving quickly it has energy than if it were moving slowly.

14. The balloon shrinks because the particles inside of it are and this puts on the sides of the balloon.

15. Inside the balloon, the temperature is and the temperature of the liquid that the balloon is touching is .

16. If the motion of the particles in the balloon continues to change in the same way, what state will the particles in the balloon change into next?

• The solid particles inside the balloon will turn into a gas.
• The gas inside will turn into a solid.
• The gas inside will turn into a liquid.
• The liquids inside the balloon will turn into a gas.

17. When a cold object encounters a warm object energy can be when they touch.

18. Which of the following best describes the contents of the balloon?

• It contains energy that fills the volume of the balloon
• It contains a lot of particles too small for us to see
• It contains a few particles too small for us to see
• It contains large particles that we can’t see because they are too far apart

19. Explain how your model shows the motion of the particles in the balloon and the liquid.

20. If energy is transferred in and out of the balloon but the balloon is sealed the whole time, what happens to the amount of matter in the balloon?

• The amount of matter decreases when energy is lost
• The amount of matter increases when energy is added
• The amount of matter decreases if energy is added or lost
• The amount of matter stays the same

21. Explain how your model from the previous question would change if the balloon was filled with liquid instead of gas.

22. Refer to student 2’s model in figure A. Your teacher asks you to add particles to the model. How would the particles in the inflated balloon compare to the particles in the deflated balloon?

• The particles in the inflated balloon would be closer together than the particles in the deflated balloon.
• There would be bigger particles in the inflated balloon than in the deflated balloon.
• The particles in the inflated balloon would be moving faster than the particles in the deflated balloon.
• There would be more particles in the inflated balloon than in the deflated balloon.